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Last updated: June 5, 2026

NES + Testosterone Gel

NES/T

  • User: Male
  • Hormonal: Hormonal
  • Delivery type:
    • Transdermal
  • Intended Duration:
    • Short-Acting
  • Development Stage: Phase II
  • Developer(s)/researcher(s): Population Council, LA Biomedical Research Institute, University of Washington, Health Decisions, NICHD, Contraline
Details
  • API: Nestorone, Testosterone
  • Target: Progesterone Receptor, Androgen Receptor
  • Mechanism of Action:
    • Reduced Sperm Production
  • Inactive Materials: Hydroalcoholic Gel
  • Regimen: 1 Application/Day
  • MPT: Not Potential MPT
  • Promising Attributes: NES/T, one of the furthest-advancing contraceptive products for male users currently under development, has reliable return to fertility post-use and aligns with user research that suggests interest in transdermal, user controlled delivery systems.
Product Status

Active Clinical Research

History

2005: Phase I study initiated by Population Council to evaluate whether nestorone gel in combination with testosterone gel applied transdermally will result in more effective suppression of gonadotropins than NES or T gel applied alone. 
2009: Phase I study initiated to evaluate safety and sperm + gonadotropin supression from a combined NES/T gel
2015: Phase I randomized, double-blinded trial initiated to evaluate PK and gonadotropin supression of NES/T gel
2017: Phase I open-label trial evaluating secondary exposure of female non-users to NES/T applied by male users
2018: Phase IIb open-label multi-center trial initiated to evaluate contraceptive efficacy, safety, and infertility biomarkers.
2024: Phase IIb trial concludes, enrolling 420 couples recruited through the Contraceptive Clinical Trials Network. 
2025: Contraline announces intention to exercise their exclusive licensing option for NES/T, supporting the method through Phase III clinical evaluation and commercialization.

2026: Contraline announces $92.5M series B financing led by BVF Partners and RA Capital Management to advance NES/T through Phase III trials. Contraline shares intention to initiate Phase III trial in 2027. 

Publications

Additional Information